EXPEDITION TO POINT BARROW, ALASKA. 



529 



TEMPERATURE COEFFICIENT. 



There were no special observations made to determine the effect of change of temperature on 

 the magnetic moment of the balance magnet. The instrument was mechanically compensated a.s 

 near as could be judged, and it only remains to determine the outstanding effect by means of the 

 ordinary readings. There was no thermometer in the case of the balance magnetometer, but the 

 same temperature record as was given for the bifllar magnetometer answers, since the readings of 

 the two thermometers one with the uuifilar, the other with the biiilar rarely differ more than 

 half a degree and less than 0.l Fahr., in the monthly means. Applying the same process as ill 

 the case of the bifllar, we find 



It is proposed to adopt for the present value the value (KTiO.-, winch is equivalent to a 

 decrease of 0.7 x. 0001584 (0.7 time the average value for 1 division) or .000111 part of the vertical 

 force for an increase of temperature of 1 Fahr. 



Solar-diurnal variation of the vertical force, inclusive of disturbances, and expressed in parts of the 



force; Uglaamie, 18S2-'83. 



H. Ex. 44- 



-67 



